Project description:Loss of expression of the cell-cell adhesion molecule E-cadherin is an essential event for epithelial-mesenchymal transition (EMT), a process that allows cell migration in the developing embryo and during tumour invasion. Transcriptional repression has emerged as the main mechanism responsible for E-cadherin downregulation in most carcinomas. Recently, we have identified the class I HLH transcriptional regulator E2-2 (ITF2), in a yeast one hybrid screen designed to identify transcriptional repressors interacting with the E-pal element of the murine E-cadherin promoter. The E2-2 gene codifies two isoforms that differ in their N-terminal regions but their specific functions remain unknown. In the present work we show that both E2-2A and E2-2B induce a complete EMT, in MDCK cells, with loss of E-cadherin expression, gain of mesenchymal markers and acquisition of motile and invasive properties. Although both isoforms repress E-cadherin promoter in MDCK cells, only the E2-2B isoform does it in other epithelial cell lines. Notably, we found that E2-2B is upregulated at the mRNA level in MDCK cells after treatment with TGF-ï¢1, a key regulator of EMT. Upregulation of E2-2A/B factors was confirmed in MDCK cells overexpressing other EMT inducers, Snai1, Snai2 or E47. Interestingly, gene profiling studies indicate that bHLH E2-2 factors induce similar, yet distinct, genetic programs from those induced by bHLH E47 in MDCK cells. These results, together with the expression pattern observed in early mouse embryos, support a new role for E2-2A/B in E-cadherin regulation and EMT, and suggest an interesting interplay between bHLH factors and other E-cadherin repressors. Keywords: Genetic Modification (overexpression of E-cadherin repressors) The Oncochip microarray platform v2.0 contains 13,824 clones printed by duplicate corresponding to 9,300 different genes. Each of the MDCK transfectants (E22A, E22B) were labeled with dUTP-Cy5 and hybridized against the dUTP-Cy3-labeled MDCK-CMV controls. One additional hybridizations using reciprocal fluorochrome labeling were performed (dye-swap) in each clone. Thus, a total of two hybridizations were performed for each condition.

Project description:Comparative oncology is a developing research discipline that is being used to assist our understanding of human neoplastic diseases. Companion canines are a preferred animal oncology model due to spontaneous tumor development and similarity to human disease at the pathophysiological level. We use a paired RNA sequencing (RNA-Seq)/microarray analysis of a set of four normal canine lymph nodes and ten canine lymphoma fine needle aspirates to identify technical biases and variation between the technologies and convergence on biological disease pathways. Surrogate Variable Analysis (SVA) provides a formal multivariate analysis of the combined RNA-Seq/microarray data set. Applying SVA to the data allows us to decompose variation into contributions associated with transcript abundance, differences between the technology, and latent variation within each technology. A substantial and highly statistically significant component of the variation reflects transcript abundance, and RNA-Seq proved more sensitive for detection of transcripts expressed at low levels. Latent random variation among RNA-Seq samples is also distinct in character from that impacting microarray samples. In particular, we observed variation between RNA-Seq samples that reflects transcript GC content. Platform-independent variable decomposition without a priori knowledge of the sources of variation using SVA represents a generalizable method for accomplishing cross-platform data analysis. We identified genes differentially expressed between normal lymph nodes of disease free dogs and a subset of the diseased dogs diagnosed with B-cell lymphoma using each technology. There is statistically significant overlap between the RNA-Seq and microarray sets of differentially expressed genes. Analysis of overlapping genes in the context of biological systems suggests elevated expression and activity of PI3K signaling in B-cell lymphoma biopsies compared with normal biopsies, consistent with literature describing successful use of drugs targeting this pathway in lymphomas.

Project description:Comparative oncology is a developing research discipline that is being used to assist our understanding of human neoplastic diseases. Companion canines are a preferred animal oncology model due to spontaneous tumor development and similarity to human disease at the pathophysiological level. We use a paired RNA sequencing (RNA-Seq)/microarray analysis of a set of four normal canine lymph nodes and ten canine lymphoma fine needle aspirates to identify technical biases and variation between the technologies and convergence on biological disease pathways. Surrogate Variable Analysis (SVA) provides a formal multivariate analysis of the combined RNA-Seq/microarray data set. Applying SVA to the data allows us to decompose variation into contributions associated with transcript abundance, differences between the technology, and latent variation within each technology. A substantial and highly statistically significant component of the variation reflects transcript abundance, and RNA-Seq proved more sensitive for detection of transcripts expressed at low levels. Latent random variation among RNA-Seq samples is also distinct in character from that impacting microarray samples. In particular, we observed variation between RNA-Seq samples that reflects transcript GC content. Platform-independent variable decomposition without a priori knowledge of the sources of variation using SVA represents a generalizable method for accomplishing cross-platform data analysis. We identified genes differentially expressed between normal lymph nodes of disease free dogs and a subset of the diseased dogs diagnosed with B-cell lymphoma using each technology. There is statistically significant overlap between the RNA-Seq and microarray sets of differentially expressed genes. Analysis of overlapping genes in the context of biological systems suggests elevated expression and activity of PI3K signaling in B-cell lymphoma biopsies compared with normal biopsies, consistent with literature describing successful use of drugs targeting this pathway in lymphomas. RNA was extracted from 10 lymphoma fine needle aspirates attained from companion canines. 4 normal lymph node samples were obtained from a Beagle breeding colony at Pfizer, including two samples that were taken from the same dog but different lymph nodes. This Series represents the Affymetrix gene expression only, not RNA-Seq referenced above. RNA-Seq data have been submitted to SRA as SRA059558.

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Canis lupus familiaris

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